INSECTS. 285 



ance they are said to be in the pseudimago state, and to 

 them the name duns is applied by the fly-fisher ; when 

 they change to the imago or perfect fly, they are called 

 piscatorially spinners. There are exceptions to this uni- 

 formity, as with the May-flies ; the green drake is the 

 pseudimago, and the grey drake the imago. 



The phryganidoB and ephemeridw are easily distin- 

 guished; in the former the wings lie close along the 

 back, projecting beyond the body; the antennae or 

 feelers are long, and there are no whisks ; in the latter 

 the wings stand upright from the body like a butterfly's, 

 the antennae are very short, and there are two, or occa- 

 sionally three, long delicate whisks. 



The ph/ryganidm attach their eggs to the foliage over- 

 hanging the water, whence upon hatching the larvae fall, 

 and immediately proceed to construct, of twigs or gravel, 

 miniature houses like a snail's shell, where they reside in 

 peace and safety. These cases are lined with silk, spun 

 from the insect's mouth, and are so light as not seriously 

 to impede its swimming and rambling in search of food, 

 and being open at both ends, allow him a view of the 

 outside world. The larvae live mainly on aquatic plants, 

 and when the proper time arrives, they close the ends of 

 their houses with a species of grating, and commence the 

 dormant state of the pupa. In this they remain a few 

 days, and then emerging from their case, they ascend to 

 the surface, burst their skin t and fly away in their perfect 

 state of beauty. 



The ephemeridce deposit their eggs in the water, where 

 they soon hatch, and where the grub, which lives usually 

 on clay or vegetablj matter, resides, occasionally for 



